Process of manufacturing cellular aggregate



Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE RICHARD L. LLOYD, OFNEW YORK, N. Y.,' ASSIGNOB TO DWIGHT @JLLOYD METAL- LURGIGAL COMPANY, OFNEW YORK, N. Y.,

A CORPORATION OF NEW JERSEY PROCESS OF MANUFACTURING CELLULAR AGGREGATE1T0 Drawing.

This invention relates to cellular aggregate, and more particularly, toa process for manufacturing a light-Weight, sulphur-free, cellularaggregate from Waste material.

The invention more specifically relates to a cellular aggregate suitablefor use as a filler in concrete floors, road-bed ballast and suchanalogous conditions where a light, strong material is required, and toa method of manufacturing the same from a cheap Waste product such asresidue from burned fuel.

Cellular aggregate used as above should '1 be strong, porous and light,and, if used with eral original features of iron or steel reinforcing,should preferably .be comparatively free from sulphur inasmuch as thatelement would attack the metal reinforcing.

By the present invention it is possible to convert the entire ashproduct of burned fuel into a superior material which is highly cellularand porous and is light in weight and at the same time is strong andrigid. The product is furthermore substantially free from sulphur and isof a uniform quality.

This is accomplished by spreading ash which may or may not contain someunconsumed carbon, together with the required amount of fuel, in auniform, thin layer. The surface of the layer is then ignited and thezone of combustion caused to pass progressively through the entire mass.As each zone of the layer becomes fused, the force of the gasesthemselves serves to froth or spin the fused portion into a cellularstructure which is immediately cooled as the zone of combustion passesonward, forming the desired cellular aggregate. The heat of combustionis suificient to expel any sulphur which may be present, leaving theentire mass substantiall sulphur-free.

T e invention further consists in the new .and novel features ofoperations and the new and original arrangements and combinations ofsteps in the process hereinafter described and more particularly setforth in the claims. The invention also consists in forming a producthaving the general characteristics, the new and useful applications, andthe sevutility hereinafter set fortlr and claimed.

Application filed January 18, 1927. Serial No. 161,962.

In the following description and in the claims, specific names areemployed for convenience, but they are intended to be as One method bywhich this invention may be carried out consists more specifically inshghtly moistening ashes containing some unconsumed carbon or other fueland mixing them together into a uniform, permeable mass which may bespread on a pervious support in a substantially even layer in depthslightly more than the thickness of the cellular cake it may be desiredto obtain. Obviously, if the material is in the proper condition topermit progressive combustion, the preliminary moistening may beomitted.

One surface of the layer may then be ignlted, as by the temporaryapplication of a flame, and combustion of the fuel in the mixture may becontinued internally of the layer by causing currents ofcombustion-supporting gases such as air to pass therethrougk from thesurface initially ignited to the opposite surface. The combustion thusinitiated at one surface will progress in an approximately uniform zonethrough the layer to the opposite surface.

The heat developed by this internal combustion raises the particles in agiven zone momentarily to the point of incipient fusion, and during thismoment the currents of gases passing through the layer cause the fusedparticles to be frothed or blown and spun into thin walls and filaments,which are immediately chilled and frozen by the 0001 gas currents as thezone of combustion moves on through the layer. At the same time anysulphur in the ashes is oxidized and carried away by the gases.

Thus, when the zone of combustion has passed completely through thelayer, the entire layer has been converted from small, loose particlesinto a cellular, thin-walled, honey-combed cake,which is exceedinglylight in weight compared to its bulk, but which is I at the same timerigid and strong, and which is free from sulphur.

The above process may be made continuous by using a heries or train ofsupports for the,

ash mixture to be treated, and causing such supports to be moved througha zone where currents of combustion-supporting gases may be passedthrough the layer of material on the supports, one surface of the layeron each support being ignited as the support enters the treatment zone.The internal combustion within the layer may then be carried on asheretofore described while the support passes through the treatmentzone. After completion of the treatment, the finished cake may beremoved by inverting the support or by other suitable means and thecycle repeated.

Where it is desired to employed currents of combustion-supporting gas ofhigh velocity, it is preferable to prevent agitation of the particlesamong themselves which might be occasioned by the gas currents or byother means and which might prevent the formation of a coherent cake.This may be accomplished by enclosing the layer of material between twoscreens or pervious supports in order to prevent movement duringcombustion. If desired, however, a single support may be employed andthe gaseous v currents caused to pass downwardly through the layer ofmaterial and out through the pervious support on which the materialrests. The pervious support in this case serves as a screen to preventagitation of the particles as well as a support therefor.

Ashes obtained from ordinary coal-fired furnaces have been found tocontain sufiicient unconsumed carbon for supporting combustion, but itwill of course be understood that material which contains in itselfinsufficient fuel to develop the required degree of heat I may be usedby adding suflicient fuel, such as fine coal, sawdust or othercombustible material. This is thoroughly mixed with the material and themass spread in a uniform layer and burned as described above.

In some cases it may be desirable to mix with the material being treatedsome fluxing material which will reduce the melting point of themixture. For example, to ashes which are highly siliceous, suitableproportions of limestone dust or fine iron-bearing material may beadded.

The material may be found to contain more than the small amount of fuelnecessary to furnish the necessaryheat (generally from five to tenpercent), and in such cases a suitable quantity of fuel-free material,such as clay, sands, crushed rock or the like may be added, therebyincreasing the output at little or no increased cost.

The above described process may also be applied to natural materials,such as carboniferous shales, or to waste materials in general, such,for example, as those found in mine culm banks. The carbon content ofthe mass may be controlled by adding a suitable amount of combustiblematerial, or of fuelfree material. Furthermore, the proper basic andacid content of the resultant aggregate may be obtained by the additionto the raw material of proper fluxes, such as clay, limestone, sand,etc.

If pieces of aggregate smaller than the cake formed as heretoforedescribed are desired, the cake may be broken to the desired size by anydesired means. And by using formed supports or molds for the layer to betreated, cakes of any desired shape may be obtained.

This invention provides a simple and eco nomical method for converting amaterial which is at present a waste product into a highly useful anddesirable commodity. The process may be carried out on well-knownapparatus, requiring little labor or attention. The product isexceedingly light in weight, is strong and rigid, is uniform and of ahighly superior character.

Although certain novel features of the invention have been shown anddescribed and are pointed out in the annexed claims, it will beunderstood that various omissions, substitutions and changes in theseveral steps of the process and in its operation may be made by thoseskilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A process of manufacturing cellular aggregate from waste materialsinherently containing combustible matter which comprises causingmomentary combustion of said matter whereby incipient fusion is producedand passing gases therethrough whereby the material is spun into a thin,uniform texture, and subsequently cooling said material to produce astrong, light, cellular aggregate.

2. The process of manufacturing cellular aggregate from ash whichcomprises forming said ash into a thin layer, causing momentarycombustion of each portion thereof whereby incipient fusion is produced,and spinning said ash while in a fused condition into a porous mass.

3. The process of manufacturing cellular aggregate from ash whichcomprises forming the ash into a thin layer, progressively burning saidlayer whereby each portion is momentarily heated to the point ofincipient fusion, spinning the fused ash into a porous mass and chillingsaid mass to form a strong, light, cellular structure.

4. The process of manufacturing cellular material inherently containingcombustible matter from waste material which comprises mixing materialtherewith to produce the dematerial containing unconsumed fuel whichconsists in moistening and mixing the material to a permeable mass,spreading the mass in a uniform bed on a pervious support, igniting thecombustible constituent atone surface of the bed, passing currents ofcombustion-supporting gas through the bed fromthe surfaceinitiallyignited to the opposite surface to cause combustion of the fuelinternally of the bed whereby the material is brought to the temperatureof incipient fusion, and simultaneously blowing the heated particlesinto a coherent thin-walled, cellular structure which is cooled by thegaseous currents.

6. The process of manufacturing lightweight cellular material inherentlycontaining combustible matter from material which consists in adding asmall proportion of solid fuel in the form of small particles thereto,moistening and mixing the materials to a permeable mass, spreading themass in a uniform bed on a pervious support, igniting the combustibleconstituent at one surface of the bed, passing currents ofcombustion-supporting gas through the bed from the surface initiallyignited to the opposite surface to cause combustion of the fuelinternally of the bed whereby the material is brought to the temperatureof incipient fusion, and simultaneously blowing the heated particlesinto a coherent, thin-walled, cellular structure which is cooled by thegaseous currents.

7. The process of manufacturing lightweight cellular material from wastematerial inherently containing combustible material which consists inmixing with the waste material suitable fluxing materials, spreading themixture in a uniform, permeable bed on a pervious support, igniting thecombustible constituent at one surface of the bed, passing currents ofcombustionsupporting gas through the bed from the surface initiallyignited to the opposite surface, causing a zone of combustion toprogress through the bed to heat the particles of material while in thezone of combustion to a temperature at which the flux material willreact with the waste material to form a thin, semi-plastic layer whichis blown by the gaseous currents into thinwalled cells, and chilling thecells by the cooling action of the subsequent gaseous currents as thezone of combustion advances, whereby the entire bed of material isconverted to a homogeneous, cellular, rigid cake.

8. The process of manufacturing light- I weight cellular material fromwaste products inherently containing combustible material which consistsin bringing the content of combustible material to the desired value,spreading the mixture in a uniform, permeable bed on a pervious support,igniting the combusti: ble constituent at one surface of the bed, passing currents of combustion-supportin gas through the bed from thesurface imtlaily 1gnited to the opposite surface, causing a zone ofcombustion to progress through the bed to heat the particles of materialwhile in the zone of combustion to the temperature of incipient fusionand form a thin, semi-plastic layer which is immediately blown by thegaseous currents into thin-walled cells, and chilling the cells by thecooling action of the subsequent gaseous currents as the zone ofcombustion advances, whereby the entire bed of material is graduallyconverted to a homogeneous, cellular, rigid cake.

9. The continuous process of manufacturing light-weight cellularmaterial from,

tional external heating, progressively heating the particles of waste tothe temperature of incipient fusion and immediately blowing them, whilehot, into thin-walled cells, and then chilling the cells by the coolingaction of the gaseous currents, whereby a homogeneous, cellular, rigidcake is formed in each support.

10. The continuous process of manufacturing light-weight cellularmaterial from waste inherently containing combustible matter whichconsists in mixing with the waste small proportions of fuel, spreadingthe mixture in a permeable, even bed on a series of movable, pervioussupports, adding a flux to reduce the melting point of the mixture,advancing the supports through a treatment zone in whichcombustion-supporting gases are passed through the bed, igniting thefuel at one surface of the bed immediately upon reaching the treatmentzone, and continuing combustion of the fuel internally of the bedwithout additional external heating, progressively heating the particlesof waste to the temperature of incipient fusion and immediately blowingthem, while hot, into thin-walled cells, and then chilling the cells bythe cooling action of the gaseous currents, whereby a homogeneous,cellular, rigid cake is formed in each support. 1

In testimony whereof I have hereunto set my hand.

RICHARD L. LLOYD.

